Curious if you've heard about socially-induced Tourette-like behaviours? There was a HN post about it not too long ago, one of the signs was sudden onset later in life: https://news.ycombinator.com/item?id=33878155
Funny you mention this, because it was only when that story came out that I could even find info about sudden onset Tourette's in people. Mines is the full vocal and movement ticks. But ticks only happen when I get memory flashbacks, which are approximately 50-100 times a day.